Coronary microvascular spasm causes myocardial ischemia in patients with vasospastic angina

Coronary spasm and vasomotor dysfunction as a cause of MINOCA

Increasing evidence has shown that coronary spasm and vasomotor dysfunction may be the underlying cause in more than half of myocardial infarctions with non-obstructive coronary arteries (MINOCA) as well as an important cause of chronic chest pain in the outpatient setting. We review the contemporary understanding of coronary spasm and related vasomotor dysfunction of the coronary arteries, the pathophysiology and prognosis, and current and emerging approaches to diagnosis and evidence-based treatment.

Coronary Vascular (DYS) Function and Invasive Physiology Assessment: Insights into Bolus and Continuous Thermodilution Methods

A considerable number of patients with angina or myocardial ischemia have no significant coronary artery disease on invasive angiography. In recent years, several steps towards a better comprehension of the pathophysiology of these conditions, angina or ischemia with non-obstructive coronary arteries (ANOCA/INOCA), have been made. Nevertheless, several gaps in knowledge still remain. This review is intended to provide a comprehensive overview of ANOCA and INOCA, with a particular focus on pathophysiology, recent diagnostic innovations, gaps in knowledge and treatment modalities.

Coronary Microvascular Spasm: Clinical Presentation and Diagnosis

Professor Maseri pioneered the research and treatment of coronary vasomotion abnormalities represented by coronary vasospasm and coronary microvascular dysfunction (CMD). These mechanisms can cause myocardial ischaemia even in the absence of obstructive coronary artery disease, and have been appreciated as an important aetiology and therapeutic target with major clinical implications in patients with ischaemia with non-obstructive coronary artery disease (INOCA). Coronary microvascular spasm is one of the key mechanisms responsible for myocardial ischaemia in patients with INOCA. Comprehensive assessment of coronary vasomotor reactivity by invasive functional coronary angiography or interventional diagnostic procedure is recommended to identify the underlying mechanisms of myocardial ischaemia and to tailor the best treatment and management based on the endotype of INOCA. This review highlights the pioneering works of Professor Maseri and contemporary research on coronary vasospasm and CMD with reference to endothelial dysfunction, Rho-kinase activation and inflammation.

Sex-related differences in coronary vasomotor disorders: Comparisons between Western and Japanese populations

Sex-related differences in the prevalence of cardiac disorders have been elucidated beyond races. Angina/ischemia with nonobstructive coronary artery disease (AINOCA) is often observed in females. Coronary microvascular dysfunction (CMD) and coronary epicardial spasm (CES) are the principal cause of AINOCA. The clinical outcomes of Western patients with CMD were less satisfactory than expected, while the prognosis of Japanese patients with CES treated with medications including calcium channel blockers was favorable. However, the incidence and clinical features of coronary spasm endotypes were different between Western and Japanese populations. Furthermore, sex-related differences in the clinical manifestations and outcomes of patients with different spasm endotypes remain uncertain beyond race. In this article, we will review the sex differences in Japanese AINOCA patients with coronary vasomotor disorders, including CMD and CES, and compare them with those of Western patients.

Non-invasive diagnosis of vasospastic angina

Vasospastic angina (VSA), or variant angina, is an under-recognized cause of chest pain and myocardial infarction, especially in Western countries. VSA leads to a declined quality of life and is associated with increased morbidity and mortality. Currently, the diagnosis of VSA relies on invasive testing that requires the direct intracoronary administration of ergonovine or acetylcholine. However, invasive vasoreactivity testing is underutilized. Several non-invasive imaging alternatives have been proposed to screen for VSA. This review aims to discuss the strengths and limitations of available non-invasive imaging tests for vasospastic angina.

Resting coronary flow drives the daily pattern in coronary flow reserve in patients with chest pain without obstructive epicardial stenosis

Objectives

Ischemia with no obstructive coronary artery disease (INOCA) is a risk factor for major adverse cardiovascular events and is characterized by abnormal coronary microvascular tone. In patients with INOCA, adverse cardiovascular events most commonly occur in the morning compared to other times of the day and night.

Materials and methods

We tested whether coronary microvascular function varies diurnally with attenuation in the morning in patients with symptomatic coronary artery disease without significant (>50%) epicardial stenosis. We evaluated data from 17 patients studied in the AM (700-1159 h) and 11 patients in the PM (1200-1800 h). Coronary microvascular function was measured using perfusion contrast imaging at rest and after infusion of intravenous regadenoson. We calculated microvascular flow reserve as the ratio of hyperemic to resting flow. Along with independent sample t-tests, we performed bootstrapping procedures to test mean differences between AM and PM groups, using the bias-corrected and accelerated method with 5,000 bootstrapped samples.

Results and conclusion

The AM and PM groups were matched for demographic and existing risk factors. Coronary microvascular flow reserve was ∼33% higher in the AM compared to the PM (P = 0.025, BCa 95% CI [0.25, 1.64]; Hedge's g = 0.89, 95% CI [0.11, 1.66]) as a result of significantly lower resting flow (∼50%) in the AM compared to the PM (P = 0.03, M Diff = -56.65, BCa 95% CI [-118.59, -2.12]; Hedge's g = -0.86, 95% CI [-1.60, -0.06]). Our observations are of clinical value and can influence diagnosis and treatment in the clinic based on the time of day of measurements.

Is Adrenaline Always the First Choice Therapy of Anaphylaxis? An Allergist-cardiologist Interdisciplinary Point of View

Worldwide, adrenaline is considered the first choice therapy in the international guidelines for the management of anaphylaxis. However, the heart and cardiovascular apparatus are strongly involved in anaphylaxis; for that reason, there are some cardiac conditions and certain anaphylaxis patterns that make epinephrine use problematic without adequate heart monitoring. The onset of Kounis syndrome, takotsubo cardiopathy, or the paradoxical anaphylaxis require great attention in the management of anaphylaxis and adrenaline administration by clinicians, who should be aware of the undervalued evolution of anaphylaxis and the potential cardiologic complications of epinephrine administration. Numerous case reports and studies describe the unexpected onset of cardiac diseases following epinephrine treatment, despite the latter being the recommended therapy for anaphylaxis. Our review suggests that future anaphylaxis guidelines should incorporate cardiovascular specialists since the treatment of Kounis syndrome or takotsubo cardiopathy requires cardiologist skills.

Phenotype-based management of coronary microvascular dysfunction

40-70% of patients undergoing invasive coronary angiography with signs and symptoms of ischemia are found to have no obstructive coronary artery disease (INOCA). When this heterogeneous group undergo coronary function testing, approximately two-thirds have demonstrable coronary microvascular dysfunction (CMD), which is independently associated with adverse prognosis. There are four distinct phenotypes, or subgroups, each with unique pathophysiological mechanisms and responses to therapies. The clinical phenotypes are microvascular angina, vasospastic angina, mixed (microvascular and vasospastic), and non-cardiac symptoms (reclassification as non-INOCA). The Coronary Vasomotor Disorders International Study Group (COVADIS) have proposed standardized criteria for diagnosis. There is growing awareness of these conditions among clinicians and within guidelines. Testing for CMD can be done using invasive or non-invasive modalities. The CorMicA study advocates the concept of 'functional angiography' to guide stratified medical therapy. Therapies broadly fall into two categories: those that modulate cardiovascular risk and those to alleviate angina. Management should be tailored to the individual, with periodic reassessment for efficacy. Phenotype-based management is a worthy endeavor for both patients and clinicians, aligning with the concept of 'precision medicine' to improve prognosis, symptom burden, and quality of life. Here, we present a contemporary approach to the phenotype-based management of patients with INOCA.

Prognostic Impact of Chronic Vasodilator Therapy in Patients With Vasospastic Angina

Background

Chronic vasodilator therapy with long‐acting nitrate is frequently used to treat vasospastic angina. However, the clinical benefits of this approach are controversial. We investigated the prognostic impact of vasodilator therapy in patients with vasospastic angina from the multicenter, prospective VA‐KOREA (Vasospastic Angina in KOREA) registry.

Methods and Results

We analyzed data from 1895 patients with positive intracoronary ergonovine provocation test results. The patients were divided into 4 groups: no vasodilator (n=359), nonnitrate vasodilator (n=1187), conventional nitrate (n=209), and a combination of conventional nitrate and other vasodilators (n=140). The primary end point was a composite of cardiac death, acute coronary syndrome, and new‐onset arrhythmia at 2 years. Secondary end points were the individual components of the primary end point, all‐cause death, and rehospitalization due to recurrent angina.

The groups did not differ in terms of the risk of the primary end point. However, the acute coronary syndrome risk was significantly higher in the conventional nitrate (hazard ratio [HR], 2.49; 95% CI, 1.01–6.14; P=0.047) and combination groups (HR, 3.34; 95% CI, 1.15–9.75, P=0.027) compared with the no‐vasodilator group, as assessed using the inverse probability of treatment weights. Subgroup analyses revealed prominent adverse effects of nitrate in patients with an intermediate positive ergonovine provocation test result and in those with low Japanese Coronary Spasm Association scores.

Conclusions

Long‐acting nitrate‐based chronic vasodilator therapy was associated with an increased 2‐year risk of acute coronary syndrome in patients with vasospastic angina, especially in low‐risk patients.

Prevalence of Coronary Microvascular Disease and Coronary Vasospasm in Patients With Nonobstructive Coronary Artery Disease: Systematic Review and Meta-Analysis

Background

A relevant proportion of patients with suspected coronary artery disease undergo invasive coronary angiography showing normal or nonobstructive coronary arteries. However, the prevalence of coronary microvascular disease (CMD) and coronary spasm in patients with nonobstructive coronary artery disease remains to be determined. The objective of this study was to determine the prevalence of coronary CMD and coronary vasospastic angina in patients with no obstructive coronary artery disease.

Methods and Results

A systematic review and meta‐analysis of studies assessing the prevalence of CMD and vasospastic angina in patients with no obstructive coronary artery disease was performed. Random‐effects models were used to determine the prevalence of these 2 disease entities. Fifty‐six studies comprising 14 427 patients were included. The pooled prevalence of CMD was 0.41 (95% CI, 0.36–0.47), epicardial vasospasm 0.40 (95% CI, 0.34–0.46) and microvascular spasm 24% (95% CI, 0.21–0.28). The prevalence of combined CMD and vasospastic angina was 0.23 (95% CI, 0.17–0.31). Female patients had a higher risk of presenting with CMD compared with male patients (risk ratio, 1.45 [95% CI, 1.11–1.90]). CMD prevalence was similar when assessed using noninvasive or invasive diagnostic methods.

Conclusions

In patients with no obstructive coronary artery disease, approximately half of the cases were reported to have CMD and/or coronary spasm. CMD was more prevalent among female patients. Greater awareness among physicians of ischemia with no obstructive coronary arteries is urgently needed for accurate diagnosis and patient‐tailored management.

Pathophysiology and Diagnosis of Coronary Functional Abnormalities

Approximately one-half of patients undergoing diagnostic coronary angiography for angina have no significant coronary atherosclerotic stenosis. This clinical condition has recently been described as ischaemia with non-obstructive coronary arteries (INOCA). Coronary functional abnormalities are central to the pathogenesis of INOCA, including epicardial coronary spasm and coronary microvascular dysfunction composed of a variable combination of increased vasoconstrictive reactivity and/or reduced vasodilator function. During the last decade - in INOCA patients in particular - evidence for the prognostic impact of coronary functional abnormalities has accumulated and various non-invasive and invasive diagnostic techniques have enabled the evaluation of coronary vasomotor function in a comprehensive manner. In this review, the authors briefly summarise the recent advances in the understanding of pathophysiology and diagnosis of epicardial coronary artery spasm and coronary microvascular dysfunction.

Intracoronary acetylcholine testing among 746 consecutive Japanese patients with angina-like chest pain and unobstructed coronary artery disease

Aims 

Intracoronary acetylcholine (ACh) testing is useful for the detection of epicardial spasm (ES) and coronary microvascular spasm (CMS). We retrospectively analysed the incidence of ES and CMS in consecutive Japanese patients with unobstructed coronary artery disease.

Methods and results

From January 1991 to February 2019, we performed intracoronary ACh testing of 1864 patients. Among these patients, a total of 746 consecutive patients (254 women, mean age 64 ± 11 years) who underwent first diagnostic angiography for suspected myocardial ischaemia and had unobstructed coronary arteries (<50%) were enrolled. Epicardial spasm was defined as ≥90% stenosis and usual chest symptoms and ischaemic ECG changes, while CMS was defined as <75% stenosis and usual chest symptoms and ischaemic ECG changes. We performed intracoronary ACh testing on both coronary arteries in 96% (716/746) of all subjects. Overall, ES was found in 329 patients (44%), whereas CMS was revealed in 40 patients (5%) including 4 patients with coexisting ES. In patients with ES, women made up 22%, and approximately three-quarters of the patients had resting chest pain. In contrast, women composed 65% (26/40) of those with CMS, and 15 patients with CMS had another chest symptom. Coronary microvascular spasm was frequently observed in the left coronary artery (LCA) but not the right coronary artery. Electrical cardioversion was necessary for two patients.

Conclusions 

Coronary microvascular spasm was recognized in only 5% of consecutive Japanese patients with unobstructed coronary artery disease, whereas ES was revealed in 44% of those patients. Coronary microvascular spasm was often observed in women and in the LCA.

Role of cardiovascular magnetic resonance in the prognosis of patients with myocardial infarction with non-obstructive coronary arteries

BACKGROUND

It is estimated that 5% to 10% of patients with myocardial infarction (MI) present with no obstructive coronary artery lesions. Until now, most studies have focused on acute coronary syndrome, including different clinical entities with a similar presentation encompassed under the term MINOCA (MI with non-obstructive coronary arteries). The aim of this study is to assess the prognosis of patients diagnosed with true infarction, confirmed by cardiovascular magnetic resonance (CMR), in the absence of significant coronary lesions.

METHODS

Prospective multicenter registry study, including 120 consecutive patients with a CMR-confirmed MI without obstructive coronary artery lesions. The primary clinical outcome was major adverse cardiovascular events (MACE: death, non-fatal infarction, stroke, or cardiac readmission), assessed over three years.

RESULTS

Seventy-six patients (63.3%) were admitted with a diagnosis of acute coronary syndrome, and 44 (36.6%) for other causes (mainly heart failure); the definitive diagnosis was established by CMR. Most patients (64.2%) were men, and the mean age was 58.8 ± 13.5 years. Patients presented with small infarcts: 83 (69.1%) showed late gadolinium enhancement (LGE) in one or two myocardial segments, mainly transmural (in 77.5% of patients) and with a preserved left ventricular ejection fraction (median 54.8%, interquartile range 37-62). The most frequent infarct location was inferolateral (n = 38, 31.7%). During follow-up, 43 patients (35.8%) experienced a MACE, including 9 (7.5%) who died. In multivariable analysis, LGE in two versus one myocardial segment doubled the risk of adverse cardiac events (hazard ratio [HR] 2.32, 95% confidence interval [CI] 0.97-5.83, p = 0.058). Involvement of three or more myocardial segments almost tripled the risk (HR 2.71, 95% CI 1.04-7.04, p = 0.040 respectively).

CONCLUSIONS

Patients with true MI but without significant coronary artery lesions predominantly had small infarcts. Myocardial 3-segment LGE involvement is associated with a significantly higher risk of adverse cardiac events.

Safety assessment and results of coronary spasm provocation testing in patients with myocardial infarction with unobstructed coronary arteries compared to patients with stable angina and unobstructed coronary arteries

BACKGROUND

Coronary spasm is an established cause for myocardial infarction with unobstructed coronary arteries, and can be diagnosed using intracoronary acetylcholine testing. However, it has been questioned whether such testing is feasible and safe in the acute phase. The aim of this study was to assess the frequency of coronary spasm and the safety of the acetylcholine test in patients with myocardial infarction with unobstructed coronary arteries compared to patients with stable angina and unobstructed coronaries.

METHODS

One hundred and eighty selected patients (52% women, mean age 62±13 years) with either myocardial infarction with unobstructed coronary arteries (n=80) or stable angina and unobstructed coronaries (n=100) were enrolled from 2007-2018. All patients underwent the acetylcholine test according to a standardised protocol immediately after diagnostic angiography. Apart from assessment of clinical, demographic and risk factor data, side effects and complications during the acetylcholine test were recorded.

RESULTS

Overall, epicardial spasm was found in 26% with a higher prevalence among the myocardial infarction with unobstructed coronary arteries compared to the stable angina patients (35% vs 19%, p=0.017). Microvascular spasm was found in 42% with a higher prevalence among the stable patients compared to the myocardial infarction with unobstructed coronary arteries cohort (53% vs 29%, p=0.0014). There were no statistically significant differences in the rate of side effects (16% vs 14%, p=0.674) or complications (1% vs 2.5%, p=0.438) between the two groups. None of the patients experienced irreversible complications.

CONCLUSION

Coronary spasm is a frequent cause for myocardial infarction with unobstructed coronary arteries. Spasm provocation testing using acetylcholine is feasible in such patients in the acute phase. The complication rate during acetylcholine testing in myocardial infarction with unobstructed coronary arteries patients is low and comparable to patients with stable angina.

Invasive Diagnosis of Coronary Functional Disorders Causing Angina Pectoris

Coronary vasomotion disorders represent a frequent cause of angina and/or dyspnoea in patients with non-obstructed coronary arteries. The highly sophisticated interplay of vasodilatation and vasoconstriction can be assessed in an interventional diagnostic procedure. Established parameters characterising adequate vasodilatation are coronary blood flow at rest, and, after drug-induced vasodilation, coronary flow reserve, and microvascular resistance (hyperaemic microvascular resistance, index of microcirculatory resistance). An increased vasoconstrictive potential is diagnosed by provocation testing with acetylcholine or ergonovine. This enables a diagnosis of coronary epicardial and/or microvascular spasm. Ischaemia associated with microvascular spasm can be confirmed by ischaemic ECG changes and the measurement of lactate concentrations in the coronary sinus. Although interventional diagnostic procedures are helpful for determining the mechanism of the angina, which may be the key to successful medical treatment, they are still neither widely accepted nor applied in many medical centres. This article summarises currently well-established invasive methods for the diagnosis of coronary functional disorders causing angina pectoris.

Sex-based differences in revascularization and 30-day readmission after ST-segment-elevation myocardial infarction in the United States

BACKGROUND

Cardiovascular disease is the leading cause of death for women in the United States. Revascularization is considered the standard of care for treatment of ST-segment elevation myocardial infarction (STEMI) and is known to reduce readmission. However there is a paucity of data that examines the sex-dependent impact of revascularization on readmission. We aimed to investigate sex differences in revascularization rates, 30-day readmission rates, and primary cause of readmissions following STEMIs.

METHODS

STEMI hospitalizations were selected in the Nationwide Readmissions Database from 2010 to 2014. Revascularization rates, 30-day readmission rates, and primary cause of readmission were examined. Interaction between sex and revascularization was assessed. Multivariable regression analysis was performed to identify predictors of 30-day readmission and revascularization for both sexes.

RESULTS

219,944 women and 489,605 men were admitted with STEMIs. Women were more likely to be older, and have more comorbidities. Women were less likely to undergo revascularization by percutaneous coronary intervention (adjusted odds ratio [OR]: 0.68; 95% confidence interval [CI]: 0.66-0.70) or coronary artery bypass graft surgery (adjusted OR 0.40; CI 0.39-0.44). Women had higher 30-day readmission rates (15.7% vs. 10.8%, p < 0.001; OR 1.20, CI 1.17-1.23), and revascularization in women was not associated with a decreased likelihood of 30-day readmission. The primary cardiac cause of readmission in women was heart failure.

CONCLUSION

Compared to men, women with STEMIs had lower rates of revascularization and higher rates of 30-day readmission. When revascularized, women were still more likely to be readmitted as compared to non-revascularized women.

Beneficial effects of exercise training on physical performance in patients with vasospastic angina

AIMS

In vasospastic angina (VSA), coronary vasomotion abnormalities could develop not only in epicardial coronary arteries but also in coronary microvessels, where calcium channel blockers (CCBs) have limited efficacy. However, efficacy of exercise training for VSA remains to be elucidated. We thus aimed to examine whether vasodilator capacity of coronary microvessels is impaired in VSA patients, and if so, whether exercise exerts beneficial effects on the top of CCBs.

METHODS

We performed 2 clinical protocols. In the protocol 1, we measured myocardial blood flow (MBF) using adenosine-stress dynamic computed tomography perfusion (CTP) in 38 consecutive VSA patients and 17 non-VSA controls. In the protocol 2, we conducted randomized controlled trial, where 20 VSA patients were randomly assigned to either 3-month exercise training group (Exercise group) or Non-Exercise group (n= 10 each).

RESULTS

In the protocol 1, MBF on CTP was significantly decreased in the VSA group compared with the Non-VSA group (138 ± 6 vs 166 ± 10 ml/100 g/min, P = 0.02). In the protocol 2, exercise capacity was significantly increased in the Exercise group than in the Non-Exercise group (11.5 ± 0.5 to 15.4 ± 1.8 vs 12.6 ± 0.7 to 14.0 ± 0.8 ml/min/kg, P < 0.01). MBF was also significantly improved after 3 months only in the Exercise group (Exercise group, 145 ± 12 to 172 ± 8 ml/100 g/min, P < 0.04; Non-Exercise group, 143 ± 14 to 167 ± 8 ml/100 g/min, P = 0.11), although there were no significant between-group differences.

CONCLUSIONS

These results provide the first evidence that, in VSA patients, exercise training on the top of CCBs treatment may be useful to improve physical performance, although its effect on MBF may be minimal.

Gender Differences in Endothelial Function and Coronary Vasomotion Abnormalities

Introduction:

Structural and functional abnormalities of coronary microvasculature, referred to as coronary microvascular dysfunction (CMD), have been implicated in a wide range of cardiovascular diseases and have gained growing attention in patients with chest pain with no obstructive coronary artery disease, especially in females. The central mechanisms of coronary vasomotion abnormalities encompass enhanced coronary vasoconstrictive reactivity (ie, coronary spasm), reduced endothelium-dependent and -independent coronary vasodilator capacities, and increased coronary microvascular resistance. The 2 major endothelium-derived relaxing factors, nitric oxide (NO) and endothelium-dependent hyperpolarization (EDH) factors, modulate vascular tone in a distinct vessel size–dependent manner; NO mainly mediates vasodilatation of relatively large, conduit vessels, while EDH factors in small resistance vessels. Endothelium-dependent hyperpolarization–mediated vasodilatation is more prominent in female resistance arteries, where estrogens exert beneficial effects on endothelium-dependent vasodilatation via multiple mechanisms. In the clinical settings, therapeutic approaches targeting NO are disappointing for the treatment of various cardiovascular diseases, where endothelial dysfunction and CMD are substantially involved.

Significance:

In this review, we will discuss the current knowledge on the pathophysiology and molecular mechanisms of endothelial function and coronary vasomotion abnormalities from bench to bedside, with a special reference to gender differences.

Results:

Recent experimental and clinical studies have demonstrated distinct gender differences in endothelial function and coronary vasomotion abnormalities with major clinical implications. Moreover, recent landmark clinical trials regarding the management of stable coronary artery disease have questioned the benefit of percutaneous coronary intervention, supporting the importance of the coronary microvascular physiology.

Conclusion:

Further characterization and a better understanding of the gender differences in basic vascular biology as well as those in cardiovascular diseases are indispensable to improve health care and patient outcomes in cardiovascular medicine.

Clinical outcomes in patients with primary stable microvascular angina: is the jury still out?

Several studies have demonstrated that angina chest pain in presence of normal or near normal coronary arteries (NCAs) is mainly related to coronary microvascular dysfunction (CMD). However, controversial findings exist about clinical outcome of these patients. In this article, we critically review characteristics and results of the main clinical studies reporting clinical outcome of stable patients with angina chest pain and non-obstructive coronary artery disease (NO-CAD). Published data indicate that clinical outcomes of these patients are heterogeneous, but those with strict criteria for primary stable microvascular angina (MVA, i.e. typical angina with NCAs mainly related to efforts) do not appear to have an increased mortality or risk of major coronary events. A major determinant of outcome in patients with MVA and NO-CAD seems instead related to non-critical atherosclerotic disease, the presence of which should suggest a more aggressive management of cardiovascular risk factors and preventive management. Future studies should assess whether CMD may have a relevant prognostic role in the latter clinical context and/or in other clinical settings of NO-CAD different from primary stable MVA.

Marked Impairment of Endothelium-Dependent Digital Vasodilatations in Patients With Microvascular Angina

Objective:

It remains to be elucidated whether and how endothelial functions are impaired in peripheral circulation of patients with coronary functional disorders, such as vasospastic angina (VSA) and microvascular angina (MVA). We simultaneously examined endothelial functions of peripheral conduit and resistance arteries in patients with coronary functional disorders, with a special reference to NO and endothelium-dependent hyperpolarization factors.

Approach and Results:

Based on the results of invasive coronary acetylcholine testing and coronary physiological measurements, we divided 43 patients into 3 groups; VSA, MVA, and VSA+MVA. Endothelium-dependent vasodilatations of the brachial artery and fingertip arterioles to intra-arterial infusion of bradykinin were simultaneously evaluated by ultrasonography and peripheral arterial tonometry, respectively. To assess NO and endothelium-dependent hyperpolarization factors, measurements were repeated after oral aspirin and intra-arterial infusion of N G -monomethyl-L-arginine. Additionally, endothelium-independent vasodilatations to sublingual nitroglycerin and plasma levels of biomarkers for endothelial functions were measured. Surprisingly, digital vasodilatations to bradykinin were almost absent in patients with MVA alone and those with VSA+MVA compared with those with VSA alone. Mechanistically, both NO- and endothelium-dependent hyperpolarization–mediated digital vasodilatations were markedly impaired in patients with MVA alone. In contrast, endothelium-independent vasodilatations to nitroglycerin were comparable among the 3 groups. Plasma levels of soluble VCAM (vascular cell adhesion molecule)-1 were significantly higher in patients with MVA alone compared with those with VSA alone.

Conclusions:

These results provide the first evidence that both NO- and endothelium-dependent hyperpolarization–mediated digital vasodilatations are markedly impaired in MVA patients, suggesting that MVA is a cardiac manifestation of the systemic small artery disease.

Percutaneous coronary intervention in women: is sex still an issue?

Coronary artery disease among women presents differences in terms of clinical presentation and pathophysiology. To date, women present worse prognoses with more events and higher mortality rate. One the one hand, they are less likely addressed for invasive therapy. One the other hand, revascularization procedures, whether by bypass or by percutaneous coronary intervention, are associated with higher rates of complications and poorer prognosis. Despite higher risk factor burden and comorbidity, women are less affected by obstructive disease and plaque characteristics are more favorable than among men. Abnormalities of endothelial function and micro vascular flow reserve could explain part of the high prevalence of symptoms of angina observed among women. Due to the worse prognosis of microvascular dysfunction, particularly in women, proper diagnosis is mandatory and deserve invasive management. Outcome following ST elevation myocardial infarction is still more severe among women with higher in-hospital mortality, but sex discrepancies are observed even in elective percutaneous coronary intervention. However, improvement of techniques, drugs and devices benefited to both men and women and tend to decrease gender gap. Especially, changes in the design of newer-generation drug-eluting stents (DES) may be particularly important for women. Female sex remains a potent predictor of higher risk of bleeding and vascular complication; thus important efforts should be promoted to develop bleeding avoidance strategies. Sex-based differences still deserve dedicated investigations in terms of physiopathology, particular hormonal impacts, and specific responses to drugs and devices.

Diagnosis of coronary microvascular dysfunction in the clinic

The coronary microcirculation plays a pivotal role in the regulation of coronary blood flow and cardiac metabolism. It can adapt to acute and chronic pathologic conditions such as coronary thrombosis or long-standing hypertension. Due to the fact that the coronary microcirculation cannot be visualized in human beings in vivo, its assessment remains challenging. Thus, the clinical importance of the coronary microcirculation is still often underestimated or even neglected. Depending on the clinical condition of the respective patient, several non-invasive (e.g. transthoracic Doppler-echocardiography assessing coronary flow velocity reserve, cardiac magnetic resonance imaging, positron emission tomography) and invasive methods (e.g. assessment of coronary flow reserve (CFR) and microvascular resistance (MVR) using adenosine, microvascular coronary spasm with acetylcholine) have been established for the assessment of coronary microvascular function. Individual patient characteristics, but certainly also local availability, methodical expertise and costs will influence which methods are being used for the diagnostic work-up (non-invasive and/or invasive assessment) in a patient with recurrent symptoms and suspected coronary microvascular dysfunction. Recently, the combined invasive assessment of coronary vasoconstrictor as well as vasodilator abnormalities has been titled interventional diagnostic procedure (IDP). It involves intracoronary acetylcholine testing for the detection of coronary spasm as well as CFR and MVR assessment in response to adenosine using a dedicated wire. Currently, the IDP represents the most comprehensive coronary vasomotor assessment. Studies using the IDP to better characterize the endotypes observed will hopefully facilitate development of tailored and effective treatments.

Role of endothelial dysfunction in determining angina after percutaneous coronary intervention: Learning from pathophysiology to optimize treatment

Endothelial dysfunction (EnD) is a hallmark feature of coronary artery disease (CAD), representing the key early step of atherosclerotic plaque development and progression. Percutaneous coronary intervention (PCI) is performed daily worldwide to treat symptomatic CAD, however a consistent proportion of patients remain symptomatic for angina despite otherwise successful revascularization. EnD plays a central role in the mechanisms of post-PCI angina, as it is strictly associated with both structural and functional abnormalities in the coronary arteries that may persist, or even accentuate, following PCI. The assessment of endothelial function in patients undergoing PCI might help to identify those patients at higher risk of future cardiovascular events and recurrent/persistent angina who might therefore benefit more from an intensive treatment. In this review, we address the role of EnD in determining angina after PCI, discussing its pathophysiological mechanisms, diagnostic approaches and therapeutic perspectives.

Severity of Chest Pain among Acute Myocardial Infarction Patients with Diagonal Branch Vessel Disease: A Pilot Study

INTRODUCTION

 Acute myocardial infarction (AMI) patients present with variable clinical manifestations such as shortness of breath, nausea, etc. among which chest pain is the most common. Previous studies have reported that the clinical presentation of AMI patients with branch vessel disease is indistinguishable from epicardial coronary vessel disease. However, our experience suggests patients with branch vessel disease experience severe chest pain, especially those with a diagonal branch. Therefore, we aim to study the association of chest pain severity with isolated diagonal branch vessel disease as a culprit vessel in AMI patients.

METHODS

 It is a retrospective case-control design, where 10 cases and 40 historic controls were recruited in the study. Cases were patients with isolated diagonal branch disease, whereas controls were patients with epicardial vessel disease in AMI. We reviewed Coronary Angiograms of adult patients who presented with acute myocardial infarction and had undergone coronary angiography at Aga Khan University Hospital, Karachi (AKUH). Information on pain scores was measured using the Numeric Pain Rating Scale (NRS) before administration of analgesics. Other relevant variables were also recorded on a pre-structured questionnaire.

RESULTS

The mean age of all the participants in the study was 60 ± 11.0 years, with 16% of the patients being women. Among all AMI patients, the intensity of chest pain in patients with isolated diagonal branch vessel disease was 2.6 units higher as compared to those with other epicardial coronary vessel diseases (p-value: <0.001; 95% CI: 1.67 - 3.46).

CONCLUSION

 This preliminary study indicates severe chest pain can be a differentiating symptom in AMI patients with diagonal branch disease. It emphasizes clinicians to look for a possibility of a diagonal branch as a culprit vessel in AMI for better judgment, as it is often overlooked. future studies may be conducted at multiple centers for larger sample size and better generalizability.

Coronary microvascular dysfunction in patients with acute coronary syndrome and no obstructive coronary artery disease

BACKGROUND

Between 10 and 15% of patients admitted for non-ST-segment elevation acute coronary syndrome (NSTE-ACS) show no obstructive coronary artery disease (NO-CAD) at angiography. Coronary microvascular spasm is a possible mechanism of the syndrome, but there are scarce data about coronary microvascular function in these patients.

OBJECTIVES

To assess coronary microvascular function in patients with NSTE-ACS and NO-CAD.

METHODS

We studied 30 patients (67 ± 10 years, 19 female) with NSTE-ACS and NO-CAD. Specific causes of NSTE-ACS presentation (e.g., variant angina, takotsubo disease, tachyarrhythmias, etc.) were excluded. Coronary blood flow (CBF) velocity response to IV ergonovine (6 µg/kg up to a maximal dose of 400 µg) was evaluated before discharge by transthoracic Doppler echocardiography. CBF response to IV adenosine (140 μg/kg/min) and cold pressor test (CPT) was also assessed after 1 month. Ten age- and sex-matched patients with non-cardiac chest pain served as controls. Vasoactive tests were repeated after 12 months in 10 NSTE-ACS patients.

RESULTS

The ergonovine/basal CBF velocity ratio was 0.79 ± 0.09 and 0.99 ± 0.01 in patients and controls, respectively (p < 0.001). The adenosine/basal CBF velocity ratio was 1.46 ± 0.2 and 3.25 ± 1.2 in patients and controls, respectively (p < 0.001), and the CPT/basal CBF velocity ratio was 1.36 ± 0.2 and 2.43 ± 0.3 in the 2 groups, respectively (p < 0.001). In 10 patients assessed after 12 months, CBF velocity responses to ergonovine, adenosine, and CPT were found to be unchanged.

CONCLUSIONS

Patients with NSTE-ACS and NO-CAD exhibit a significant coronary dysfunction, which seems to involve both an increased constrictor reactivity, likely mainly involving coronary microcirculation, and a reduced microvascular dilator function, both persisting at 12-month follow-up.

Systemic microvascular dysfunction in microvascular and vasospastic angina

Aims

Coronary microvascular dysfunction and/or vasospasm are potential causes of ischaemia in patients with no obstructive coronary artery disease (INOCA). We tested the hypothesis that these patients also have functional abnormalities in peripheral small arteries.

Methods and results

Patients were prospectively enrolled and categorised as having microvascular angina (MVA), vasospastic angina (VSA) or normal control based on invasive coronary artery function tests incorporating probes of endothelial and endothelial-independent function (acetylcholine and adenosine). Gluteal biopsies of subcutaneous fat were performed in 81 subjects (62 years, 69% female, 59 MVA, 11 VSA, and 11 controls). Resistance arteries were dissected enabling study using wire myography. Maximum relaxation to ACh (endothelial function) was reduced in MVA vs. controls [median 77.6 vs. 98.7%; 95% confidence interval (CI) of difference 2.3-38%; P = 0.0047]. Endothelium-independent relaxation [sodium nitroprusside (SNP)] was similar between all groups. The maximum contractile response to endothelin-1 (ET-1) was greater in MVA (median 121%) vs. controls (100%; 95% CI of median difference 4.7-45%, P = 0.015). Response to the thromboxane agonist, U46619, was also greater in MVA (143%) vs. controls (109%; 95% CI of difference 13-57%, P = 0.003). Patients with VSA had similar abnormal patterns of peripheral vascular reactivity including reduced maximum relaxation to ACh (median 79.0% vs. 98.7%; P = 0.03) and increased response to constrictor agonists including ET-1 (median 125% vs. 100%; P = 0.02). In all groups, resistance arteries were ≈50-fold more sensitive to the constrictor effects of ET-1 compared with U46619.

Conclusions

Systemic microvascular abnormalities are common in patients with MVA and VSA. These mechanisms may involve ET-1 and were characterized by endothelial dysfunction and enhanced vasoconstriction.

Clinical trial registration

ClinicalTrials.gov registration is NCT03193294.

Acute myocardial infarction in young women: current perspectives

Acute myocardial infarction (AMI) is the leading cause of death in women worldwide. Every year, in the USA alone, more than 30,000 young women <55 years of age are hospitalized with AMI. In recent decades, the incidence of AMI is increasing in younger women in the context of increasing metabolic syndrome, diabetes mellitus, and non-traditional risk factors such as stress, anxiety, and depression. Although women are classically considered to present with atypical chest pain, several observational data confirm that men and women experience similar rates of chest pain, with some differences in intensity, duration, radiation, and the choice of descriptors. Women also experience more number of symptoms and more prodromal symptoms compared with men. Suboptimal awareness, sociocultural and financial reasons result in pre-hospital delays in women and lower rates of access to care with resulting undertreatment with guideline-directed therapies. Causes of AMI in young women include plaque-related MI, microvascular dysfunction or vasospasm, and spontaneous coronary artery dissection. Compared with men, women have greater in-hospital, early and late mortality, as a result of baseline comorbidities. Post-AMI women have lower referral to cardiac rehabilitation with more dropouts, lower levels of physical activity, and poorer improvements in health status compared with men, with higher inflammatory levels at 1-year from index presentation. Future strategies should focus on primary and secondary prevention, adherence, and post-AMI health-related quality of life. This review discusses the current evidence in the epidemiology, diagnosis, and treatment of AMI in young women.

Taking cardiology clinical trials to the next level: A call to action

Physicians previously perceived heart disease to be a man's disease; yet, since 1984, more women have died of ischemic heart disease. Because women who develop obstructive coronary heart disease and heart failure tend to do so 10 years later than men, cardiology clinical trials that use arbitrary age cutoffs or exclusion criteria based on comorbidities and polypharmacy often limit the pool of potential participants to a greater extent for women. Issues related to trial design and insufficient accounting for female-predominant disease patterns have contributed to low rates of enrollment of women in certain domains of cardiology research. Accordingly, women do not benefit from as rich an evidence base for cardiology as men. Here, we review major sex differences in heart disease and discuss areas of cardiology research in which women have been underrepresented. Considering the widespread sex differences in cardiovascular structure and function, it is important to include balanced numbers of women and men in cardiovascular clinical trials. Beyond inclusion, sex-specific reporting is also essential. Moreover, with ongoing developments of clinical-trial methodology, it is imperative to seek innovative ways to learn as much as possible about how interventions behave in women and men. Adaptive trials are specifically identified as promising opportunities to consider sex-based analyses at interim stages, allowing sex-specific flexibility as these trials unfold. Finally, we emphasize the importance of factoring sex as a biological variable into the design, analysis, and reporting of preclinical research, because this research critically informs the design and execution of clinical trials.

Women with Stable Angina Pectoris and No Obstructive Coronary Artery Disease: Closer to a Diagnosis

A large proportion of women with chest pain have no obstructive coronary artery disease. Recent studies have demonstrated that these women continue to have symptoms and are at increased risk of cardiovascular morbidity and mortality. Coronary microvascular dysfunction (CMD) leads to an impairment of blood flow regulation to the myocardium and possible transient ischaemia. CMD is a disease entity with several pathophysiologic aspects and diagnostic modalities continue to be developed. However, due to the complexity of the disease, it remains elusive whether CMD is the explanation for the symptoms and the poor prognosis in women with angina and no obstructive coronary artery disease.

[Is coronary artery spasm a disease specific to women?]

Vasospastic angina is considered rare in Europe but with a prevalence probably underestimated and affects preferentially men in published studies, mostly involving Asian populations. Vasospastic angina in the female population have specificities in terms of pathophysiology, clinical presentation and prognosis, as well as diagnostic strategies currently recommended, that we describe from a clinical case. Although known for over 50years, vasospastic angina remains a disease still insufficiently researched, probably even less in women. This form of angina must not however be forgotten, and the appropriate diagnostic strategy must be known and used to improve prognosis.

"Mind the gap" acute coronary syndrome in women: A contemporary review of current clinical evidence

The incidence and prevalence of coronary artery disease in women has exceeded that in men over the past four decades, and although a significant decline in mortality has occurred in the past two decades, there is a growing body of evidence suggesting that there are gender differences between the clinical manifestations and course of coronary artery disease, as well as differences in treatment and treatment response. This review article considers the current literature regarding the gender-specific manifestation of acute coronary syndromes. Through the review of basic science articles, subsets of trial data, and meta-analyses, the gender-specific differences in within acute coronary syndromes are considered in terms of diagnostic dilemmas, pathophysiology, and treatment options (including pharmacological, percutaneous and surgical methods). Finally, acute coronary syndromes and their management in the special circumstance of pregnancy are also reviewed.

Stress cardiomyopathy: Is it limited to Takotsubo syndrome? Problems of definition

In 2006, Takotsubo syndrome (TTC) was described as a distinct type of stress-induced cardiomyopathy (stress cardiomyopathy). However, when thinking about Takotsubo cardiomyopathy from the viewpoints of the AHA and ESC classifications, 2 possible problems may arise. The first potential problem is that a forecast of disease outcome is lacking in the ESC classification, whereas the AHA only states that 'outcome is favorable with appropriate medical therapy'. However, based on the literature data, one can make a general conclusion that occurrence of myocardial lesions in TTC (i.e., myocardial fibrosis and contraction-band necrosis) causes the same effects as in other diseases with similar levels of myocardial damage and should not be considered to have a lesser impact on mortality. To summarise, TTC can cause not only severe complications such as pulmonary oedema, cardiogenic shock, and dangerous ventricular arrhythmias, but also damage to the myocardium, which can result in the development of potentially fatal conditions even after the disappearance of LV apical ballooning. The second potential problem arises from the definition of TTC as a stress cardiomyopathy in the AHA classification. In fact, the main factors leading to TTC are stress and microvascular anginas, since, as has been already discussed, coronary spasm can cause myocardium stunning, resulting in persistent apical ballooning. Thus, based on this review, 3 distinct types of stress cardiomyopathies exist (variant angina, microvascular angina, and TTC), with poor prognosis. Adding these diseases to the classification of cardiomyopathies will facilitate diagnosis and preventive prolonged treatment, which should include intensive anti-stress therapy.

Kounis syndrome: A concise review with focus on management

Kounis syndrome is defined as the co-incidental occurrence of an acute coronary syndrome with hypersensitivity reactions following an allergenic event and was first described by Kounis and Zavras in 1991 as an allergic angina syndrome. Multiple causes have been described and most of the data in the literature are derived from the description of clinical cases - mostly in adult patients - and the pathophysiology remains only partly explained. Three different variants of Kounis syndrome have been defined: type I (without coronary disease) is defined as chest pain during an acute allergic reaction in patients without risk factors or coronary lesions in which the allergic event induces coronary spasm that electrocardiographic changes secondary to ischemia; type II (with coronary disease) includes patients with pre-existing atheromatous disease, either previously quiescent or symptomatic, in whom acute hypersensitive reactions cause plaque erosion or rupture, culminating in acute myocardial infarction; more recently a type-III variant of Kounis syndrome has been defined in patients with preexisting coronary disease and drug eluting coronary stent thrombosis. The pathogenesis of the syndrome is discussed, and a therapeutic algorithm is proposed.

Acute coronary syndromes without coronary plaque rupture

The latest advances in plaque imaging have provided clinicians with opportunities to treat acute coronary syndrome (ACS) and provide individualized treatment recommendations based not only on clinical manifestations, angiographic characteristics, and biomarker data, but also on the findings of plaque morphology. Although a substantial proportion of ACS events originate from plaques with an intact fibrous cap (IFC), clinicians predominantly equate ACS with plaque rupture arising from thin-cap fibroatheromas. In this Review, we discuss the recent advances in our understanding of plaque morphology in ACS with IFC, reviewing contemporary data from intravascular imaging. We also explore whether use of such imaging might provide a roadmap for more effective management of patients with ACS.

Focused Cardiovascular Care for Women: The Need and Role in Clinical Practice

Over the past decade, an emerging clinical research focus on cardiovascular (CV) disease (CVD) risk in women has highlighted sex-specific factors that are uniquely important in the prevention and early detection of coronary atherosclerosis in women. Concurrently, a 30% decrease in the number of female deaths from CVD has been observed. Despite this, CVD continues to be the leading cause of death in women, outnumbering deaths from all other causes combined. Clinical practice approaches that focus on the unique aspects of CV care for women are needed to provide necessary resources for the prevention, diagnosis, and treatment of CVD in women. In addition to increasing opportunities for women to participate in CV research, Women's Heart Clinics offer unique settings in which to deliver comprehensive CV care and education, ensuring appropriate diagnostic testing, while monitoring effectiveness of treatment. This article reviews the emerging need and role of focused CV care to address sex-specific aspects of diagnosis and treatment of CVD in women.

Sex differences in the pathophysiology, treatment, and outcomes in IHD

Heart disease is the number one killer of women. Although there are many similarities between men and women, the evolving understanding of ischemic heart disease in women allow us to emphasize the important differences that need to be recognized. These differences, including symptoms at presentation, importance of particular risk factors, pathophysiology of disease, and treatments/outcomes, will be discussed in this review.

Coronary endothelial dysfunction in non-obstructive coronary artery disease: Risk, pathogenesis, diagnosis and therapy

Up to half of patients with signs and symptoms of stable ischemic heart disease have non-obstructive coronary artery disease (NoCAD). Recent evidence demonstrates that two-thirds of patients with NoCAD have demonstrable coronary endothelial dysfunction represented by microvascular or diffuse epicardial spasm following acetylcholine challenge. Patients with coronary endothelial dysfunction are recognized to have significant health services use and morbidity as well as increased risk of developing flow-limiting coronary artery disease and myocardial events, including death. Currently, there are few centers that test for this etiology owing to lack of knowledge, limited evidence for treatment options and invasive diagnostic strategies. This article reviews the pathophysiology, epidemiology, diagnosis and treatment of coronary endothelial dysfunction as a subgroup of NoCAD.

Clinical features and prognosis of type 2 myocardial infarction in vasospastic angina

BACKGROUND

Although generally the prognosis of vasospastic angina is considered excellent, vasospasm has been shown to be a cause of type 2 myocardial infarction. This study was performed to investigate the clinical characteristics and prognosis of patients with vasospastic angina complicated with type 2 myocardial infarction.

METHODS

We performed a retrospective analysis of 171 consecutive patients with definite vasospastic angina (median age, 64 years; 55.0% were male) who visited the Kameda Medical Center with chest pain and in whom cardiac troponin I level was measured between 2005 and 2013. The patients were divided into type 2 myocardial infarction and non-type 2 myocardial infarction groups. A diagnosis of type 2 myocardial infarction was based on a serum cardiac troponin I value >99th percentile upper reference limit. The primary end point was a combination of nonfatal myocardial infarction or death by any cause.

RESULTS

A total of 42 patients (24.6%) were diagnosed with type 2 myocardial infarction, and the type 2 myocardial infarction group had a higher incidence of combined end point than the non-type 2 myocardial infarction group during the median follow-up of 4.4 years (26.2% vs 9.3%, respectively, P = .008). Type 2 myocardial infarction remained an independent predictor of combined end point even after adjusting by the Japanese Coronary Spasm Association risk factors for combined end point (hazard ratio, 2.84; 95% confidence interval, 1.22-6.61; P = .02).

CONCLUSIONS

Approximately one quarter of patients with vasospastic angina were associated with type 2 myocardial infarction, and this population should be identified as a new high-risk subgroup of those with vasospastic angina requiring an alternative treatment strategy.